• Nuclear Engineering and Technology
• /
• v.52 no.3
• /
• pp.560-567
• /
• 2020

The complexity of safety critical systems of Nuclear Power Plant continues to increase rapidly due its transition from analog to digital systems. It has thus become progressively more imperative to model these systems prior to their implementation in order to meet the high performance, safety and reliability requirements. Timed Petri Nets (TPNs) have been widely used to model such systems for non-functional analysis. The paper presents a novel methodology for the analysis of the performance metrics using PN modeling. The paper uses the isomorphism property of the TPNs and the Markov chains for the performance analysis of the safety critical systems. The presented methodology has been validated on a Shutdown System of a Nuclear Power Plant.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.18 no.5
• /
• pp.695-707
• /
• 1993

Marked Petri Net(MPN) is used to analyze communication complexity with respect to the maximum number of concurrently active rendezvous. But, because it cannot represent timed & probability characteristics explicitly, it is not used to analyze the new execution time of complexity with respect to the communication. Thus to effectively analyze that execution time complexity, we propose Ada Tasking Structure Nets (ATSN) introduced restrictive conditions : net reduction rules, execution time, and probability. Finally, we show the powers of analyze of communication complexity with ATSN.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2010.05a
• /
• pp.636-638
• /
• 2010

Task scheduling is an integral part of parallel and distributed computing. Extensive research has been conducted in this area leading to significant theoretical and practical results. Stochastic reward nets (SRN) is an extension of stochastic Petri nets and provides compact modeling facilities for system analysis. In this paper, we address task scheduling model using extended timed marked graph, which is a special case of SRNs. And we analyze this model by giving reward measures in SRN.

• Journal of the Korea Society for Simulation
• /
• v.9 no.1
• /
• pp.67-81
• /
• 2000

In this paper, a new software package for modeling and simulating discrete-event dynamic systems is developed. The new software is a general-purpose, graphical tool based on timed Petri-nets and is developed using Visual Basic and Visual C++ for the window environment. It allows the user to graphically build a Petri-net model and enter input data for executing the Petri-net simulation model. It is equipped with a deadlock detection and recovery function as well as an automatic error check function. In addition, the software supports various enabling functions and distribution functions and provides various statistics for the performance measures of interests pertaining to the system. We expect the new software will be used in a wide number of applications including computer, communication and manufacturing systems.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1994.04a
• /
• pp.409-414
• /
• 1994

A FMS is a typical discrete event system exhibiting concurrency, asynchronicity and non-determinism. Torepresent a FMS with those chatcteristics, Colored and Timed Petri Nets is defined and the modeling procedure is provided in this paper. Toanalyze and evaluate the performance of a FMS, a simulation software is developed and applied to SNU FMS/CIM Center. This software enables to detect the bottleneck machine and decide the optimaldirection in case of the expansion of a FMS.

• Journal of the military operations research society of Korea
• /
• v.23 no.2
• /
• pp.1-14
• /
• 1997

TPNSim++ is the object-oriented framework for the discrete event simulation of military systems, developed by authors. The simulation world view of TPNSim++ is on the basis of activity scanning. TPNSim++ is implemented as C++ class library under Windows 95/NT. It uses the extended timed Petri nets which are called TPNSim nets for simulation modeling tool. The aim of this study is to conduct a comparative study of TPNSim++ and SLAM II in the simulation of military maintenance systems for the validation and the applicability of TPNSim++. From this study, TPNSim++ and SLAMII have given the same results under the equivalent assumption. Thus we can get the validation of TPNSim++ and its applicability to the simulation of maintenance systems.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.14 no.5
• /
• pp.511-520
• /
• 1989

Generally, Intelliget link is made of drawing picture that is amalgated in two conception of communication and processing. This is a new system of information transmission having fuction being able to handle een though the former information transmission can not be possible. That Intelligent link is to say that function of each segment by working software can be anailable at general purposed pipeline processing system, general purpose pipeline have a different working time in function of segmant, work asynchronizing pipeline. in the papers, graphic design is easy to understand the sense of sight model by Petri Net that is simple regulation. it can translate into working of asynchronzing pipeline by working of calculator of simulation.

• Journal of Korean Society for Quality Management
• /
• v.27 no.2
• /
• pp.251-262
• /
• 1999

In the automated manufacturing systems, the problem regarding how to make production activities flexible is even more important and critical than that regarding how to product large quantities, and the more flexible, if possible, the manufacturing system is, the more competitiveness and profitable factors it gets. This research, therefore, concentrated on establishing the flexibility and evaluating performance on the manufacturing system, operational flexibility is considered because of enabling the manufacturing system to get both the improvement of production rate and the adaptive ability of environment changes. For it, we used the analytical tool, GSPNs, which is a kind of timed Petri-Nets. GSPNs is competent enough to consider practical situations just like operation priorities, machine failure, randomness, concurrency and so on. Through the GSPNs analysis, it is confirmed that in the manufacturing system with operational flexibility is compatible with the traditional performances such as production rate or mean waiting time.

• Management Science and Financial Engineering
• /
• v.14 no.1
• /
• pp.23-34
• /
• 2008

In this study, we consider stationary waiting times in a Poisson driven single-server m-node queues in series. We assume that service times at nodes are independent, and are either deterministic or non-overlapped. Each node excluding the first node has a finite waiting line and every node is operated under a FIFO service discipline and a communication blocking policy (blocking before service). By applying (max, +)-algebra to a corresponding stochastic event graph, a special case of timed Petri nets, we derive the explicit expressions for stationary waiting times at all areas, which are functions of finite buffer capacities. These expressions allow us to compute the performance measures of interest such as mean, higher moments, or tail probability of waiting time. Moreover, as applications of these results, we introduce optimization problems which determine either the biggest arrival rate or the smallest buffer capacities satisfying probabilistic constraints on waiting times. These results can be also applied to bounds of waiting times in more general systems. Numerical examples are also provided.